Measuring Propylene Glycol Concentration in Brewery Chillers

20_003_08_001-Application Note-2016-09-01

Temperature is the most critical parameter for consistency and quality when brewing beer. From the mash, to pitching the yeast, to fermentation and brightening, temperature has significant effects every step from grain to bottle. Propylene glycol chillers are commonly used throughout the brewing process to chill and regulate temperature. Propylene glycol (glycol for short) is a food-grade antifreeze that can be used as part of a chilling system when a food or beverage product requires rapid cooling. Glycol chillers used in breweries generally operate several degrees below the freezing point of water (0°C), and require a strict 35% glycol to 65% water ratio that must be maintained and monitored throughout the life of the chiller. A solution containing less than 35% glycol will cause the system to freeze and possibly rupture coolant lines; a larger concentration of glycol will reduce the efficiency of the chiller system. Because the system utilises glycol and operates at temperatures below 0°C, the freezing point must also be monitored to prevent damage.

Brewers use glycol chillers throughout the entire brewing process. Wort, the boiling-hot product from breaking down the starchy malted grain, must be cooled prior to fermentation. A glycol chiller can be used to cool the wort. Once the wort is in the fermenter is sufficiently cooled to room temperature, the yeast is pitched and fermentation begins. Chilled glycol is used to maintain the ideal temperature for fermentation, which varies depending on the style of beer being brewed and strain of yeast. Cold crashing, a procedure performed once fermentation is complete, reduces the temperature rapidly and assists in clarifying the product by encouraging yeast and other suspended particles to settle and flocculate on the bottom. Crash cooling also results in the final holding temperature of the product, which is maintained during packaging and final product refrigeration.


While visiting the brewmaster at a microbrewery, a Hanna Instruments Technical Sales Consultant noticed that the customer was utilising glycol chillers. The sales consultant learned that the manufacturer of the chiller would inspect the equipment and the glycol content once a month, but the brewmaster would have preferred to check the glycol content more frequently.

HI96832 Digital Refractometer for Propylene Glycol Analysis

HI96832 Digital Refractometer for Propylene Glycol Analysis

The sales consultant recommended the HI96832 Digital Refractometer for Propylene Glycol Analysis. The brewmaster was thrilled that an affordable instrument was available, enabling him to spot check whenever he preferred. In addition to the wide measuring range of propylene glycol from 0 to 100% (%V/V), the meter also provided measurement of the associated freezing point from 0 to -51°C . When the sales consultant performed a demonstration of the meter operation, the brewmaster was astonished by the ease of use and intuitive meter design. Furthermore, the digital display and automatic temperature compensation were a significant upgrade from the manual refractometer the brewery had used in the past. Due to the sales consultant’s attentiveness and honesty, Hanna Instruments became a reputable source for any other of the brewery ’s testing needs.


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